The present invention relates to seals, often referred to as gaskets, for making a fluid or gas tight joint between opposed mating surfaces. More particularly, the present invention relates to retainers for positioning seals between opposed mating surfaces.
Ring seals are typically annularly shaped, defining an axially aligned hole for gas or fluid passage, two axially opposed end surfaces, a radial inner surface and a radial outer surface. The most simplistic ring seal includes planar end surfaces and smooth circular radial inner and outer surfaces which define the inner diameter (ID) and outer diameter (OD) of the ring seal.
An additional commonly used ring seal is circular and has a radial cross-section of a xe2x80x9cCxe2x80x9d shape. These xe2x80x9cC sealsxe2x80x9d are constructed with the open side of the C construction facing the center of the ring such as described in U.S. Pat. No. 5,354,072, or with the open side of the C facing away from the center of the ring. As two mating surfaces are brought together with the C seal in the middle, the C seal is compressed with the open side of the C cross-section closing during compression. The ductile properties of the seal permit plastic deformation to occur without damaging the mating surfaces.
Additional seals which have been available include xe2x80x9cV sealsxe2x80x9d which are also circular, but instead of having a xe2x80x9cCxe2x80x9d cross-section, the V seal has a xe2x80x9cVxe2x80x9d cross-section with the low point of the V constructed to point either inwardly or outwardly towards the center of the seal. Moreover, seals in the art include xe2x80x9cZ sealsxe2x80x9d and simple xe2x80x9cO ringsxe2x80x9d.
The above described ring seals often include a recessed sealing surface. With reference to FIGS. 1 and 4, the typical ring seal 1 includes an annular body configuration and a circumferential groove 15 formed on the ring seal""s outer radial surface. In addition, the ring seal includes a recessed sealing surface 19 formed into each of the axial end surfaces. With reference to FIG. 28, in operation, the opposed mating surfaces 17 of the sealing assembly engage and form an air or fluid tight seal at the ring seal""s recessed sealing surface. However, the opposed mating surfaces typically do not engage or form a seal at the ring seal""s recessed regions. The sealing surface is recessed to protect the surface from becoming damaged during handling. For example, ring seals having planar surfaces often become scratched when placed on flat surfaces due to dirt or metal shavings scratching the ring seal""s sealing surface. To overcome this drawback, the ring seal""s sealing surface is recessed so as to not come into contact with debris prior to assembly within a sealing assembly. Unfortunately, ring seals having recessed sealing surfaces are expensive to manufacture and the recessed sealing surface is very difficult to polish.
Retainers are often used to hold and position a ring seal in place between two opposed mating surfaces. Retainers have been constructed in various forms. For example, U.S. Pat. No. 5,340,170 describes a retainer for positioning a gasket in a pipe joint. The retainer includes a cylindrical sidewall, an inwardly extending edge for engaging a ring seal and a plurality of claws for grabbing a pipe.
Meanwhile, U.S. Pat. No. 5,423,580 discloses a retainer having a semicircular sidewall for grasping the outer edge of a ring seal and extremity of a pipe. Moreover, additional retainer arrangements are disclosed in U.S. Pat. Nos. 4,552,389; 4,650,227; and 4,838,583.
An additional prior art ring seal and retainer assembly is shown in FIGS. 1-4. The ring seal includes a typical annular body configuration and circumferential groove formed on the ring seal""s outer radial surface. In addition, the ring seal includes a recessed sealing surface 19 formed on each of the axial end surfaces. The retainer is obtained from a single loop of a coil spring, which is then formed into a circular band. The coil retainer is positioned within the ring seal""s circumferential groove so that the outer edge of the coil projects outwardly beyond the edge of the ring seal. Meanwhile, the opposed mating surfaces include a fitting including a recess sized and positioned for receipt of the coil retainer""s edge. Once press fit into place, the retainer is restrained from inadvertent movement.
Unfortunately, the above-described retainers all suffer from significant disadvantages. For example, the coil retainer and sharp edges of the ring seal are prone to scratching, or otherwise harming, the opposed mating surfaces. This can impede the ring seal""s ability to provide a gas or fluid tight seal. Moreover, ring seals having a recessed sealing surface are expensive to manufacture. Meanwhile, the retainer described in U.S. Pat. No. 5,340,170 is capable of use only with a ring seal of an unusual construction. Furthermore, the retainer disclosed in U.S. Pat. No. 5,423,580 also does not protect the edge of a ring seal from unwantingly scratching one of the opposed mating surfaces.
Thus, it would be desirable to provide an improved ring seal and retainer assembly which is inexpensive to manufacture and easy to use.
In addition, it would be desirable to provide an improved ring seal and retainer assembly which does not require recessed sealing surfaces which are expensive to manufacture and difficult to polish.
Moreover, it would be desirable to provide an improved ring seal and retainer assembly which provides protection against damage to a ring seal""s sealing surfaces, while not being susceptible to scratching or otherwise marring the opposed mating surfaces prior to forming an air-tight or gas-tight seal.
The present invention addresses the aforementioned disadvantages by providing an improved ring seal and retainer assembly. To this end, the ring seal is annularly shaped having an axially aligned hole for gas or fluid passage. The ring seal further includes a radial inner surface, a radial outer surface and first and second axial end surfaces. Meanwhile, the retainer is circular in shape, and includes a sidewall which is sized and positioned to cover and engage the ring seal""s radial outer surface. The sidewall protects the ring seal""s radial outer surface from becoming damaged prior to assembly within a sealing assembly, and protects the opposed mating surfaces from being damaged by preventing the ring seal""s outer edge from scratching the opposed mating surfaces during assembly. Moreover, preferably, the retainer""s circular sidewall projects axially beyond the ring seal""s axial end surfaces. The protruding extremities of the circular sidewall protect the ring seal""s axial end surfaces during storage and transportation, thereby eliminating the need for the ring seal having a recessed sealing surface.
The annular retainer includes means for affixing the retainer""s circular sidewall adjacent to the ring seal""s radial outer surface. In a first embodiment, to maintain the annular retainer affixed to the ring seal, the ring seal includes a circumferential groove which circumnavigates the ring seal""s radial outer surface. The circumferential groove may be constructed in similar form to grooves constructed in the prior art; such as the groove including planar walls forming a squared indent. Alternatively, the circumferential groove may be formed in alternative configurations, such as V-shaped or rounded recesses as can be determined by those skilled in the art. Meanwhile, the annular retainer includes a circumferential ridge sized and positioned to project inwardly from the retainer""s circular sidewall into the ring seal""s circumferential groove. The circumferential ridge projects into the ring seal""s groove to inhibit the annular retainer from inadvertently being dislodged or disengaged from the ring seal.
In an alternative embodiment, the annular retainer does not include a single ridge which circumnavigates the annular retainer""s interior surface, but instead includes a plurality of ridges which only partially circumnavigate the annular retainer""s inner surface. Again, however, the ridges are sized and positioned to project into the ring seal""s circumferential groove. In a preferred embodiment, the annular retainer is provided with three ridges positioned at 120xc2x0 increments around the annular retainer.
In still an additional embodiment of the invention, the annular retainer does not include any inwardly projecting ridges to affix the retainer sidewall adjacent to the ring seal""s radial outer surface. Instead, the annular retainer is formed having an inwardly facing xe2x80x9cCxe2x80x9d shaped cross-section. To this end, the annular retainer""s circular sidewall includes upper and lower inwardly projecting edges which grasp the ring seal""s axial end surfaces.
The first and second edges of the circular sidewall partially cover and engage the ring seal""s axial end surfaces to affix the annular retainer to the ring seal. However, the axial end surfaces remain substantially uncovered by the sidewall edges so that the axial end surfaces can engage and form a seal with two axially opposed mating surfaces. Moreover, the edges project axially beyond the axial end surfaces to provide protection for the axial end surface, thereby eliminating the need for the ring seal including recessed sealing surfaces.
In an additional preferred embodiment of the invention, the annular retainer includes one or more detents which project radially outward from the annular retainer""s circular sidewall. The detents are provided to project into a fittings recess to maintain the ring seal and retainer assembly in place between opposed mating surfaces. In one embodiment, the annular retainer is provided with two or three detents which are positioned uniformly (180xc2x0 or 120xc2x0) around the annular retainer""s circular sidewall. In an additional embodiment, the annular retainer includes only a single detent which is formed around the entire circumference of the annular retainer.
It is thus an object of the present invention to provide a ring seal and retainer assembly which is very reputable, of high quality, inexpensive to manufacture and reliable for providing a seal between two planar surfaces.
It is still an additional object of the invention to provide an improved ring seal and retainer assembly which does not require recessed sealing surfaces which are expensive to manufacture and difficult to polish.
Moreover, it is an object of the present invention to provide an improved ring seal and retainer assembly which provides protection against damage to a ring seal""s sealing surfaces, while not being susceptible to scratching or otherwise marring the opposed mating surfaces prior to forming an air-tight or gas-tight seal.
It is an additional object of the invention to provide a ring seal and retainer assembly which is not prone to being scratched or damaged, and which is not prone to scratching or damaging the mating surfaces between which a seal is sought.